# Five Gulf of Mexico mesopelagic species have effective population size below viability threshold

- Published: 2026-11-14 07:34 UTC
- Section: Planet › Ecology & recycling
- Tags: mesopelagic zone, Gulf of Mexico deep sea, effective population size, genomic diversity decline, lanternfishes, deep-sea shrimp, DEEPEND consortium, extinction risk indicators
- URL: https://realtech.media/news/rt-6b5812631fa2eac0dc7ab3ad_five_gulf_of/

**Genomic data from fish and shrimp sampled in 2011–2023 show signs linked to extinction risk that abundance counts alone had not revealed.**

![Five Gulf of Mexico mesopelagic species have effective population size below viability threshold](https://realtech.media/media/2026/11/36d9437f4759db3b.png)
*nature.com*

A team led by Pedro A. Peres of Florida International University combined genomic data with ecological niche modeling to assess five mesopelagic species in the Gulf of Mexico, according to a study on nature.com [1]. Samples were collected from 2011 to 2023, which the authors describe as one of the longest time series for mesopelagic fauna in oceanographic history [1]. After quality checks, DNA from 486 animals went into the final analysis.

## Species and sampling

The animals came from the DEEPEND consortium, a program set up after the 2010 Deepwater Horizon spill, when 4–4.9 million barrels of oil were released at about 1,500 m depth [1]. Crews aboard the research vessel Point Sur used six nets that open and close at set depths, sampling from the surface to about 1,500 m. The team chose five of the most numerous animals at 200–1,000 m: three lanternfishes (Ceratoscopelus warmingii, Diaphus dumerilii, Lepidophanes guentheri) and two shrimp (Phorcosergia grandis, Robustosergia robusta).

Earlier work had recorded abundance declines of 62–80% over the last 15 years in many deep-pelagic fishes, crustaceans, cephalopods and toothed whales [1]. It was not known whether genetic diversity had fallen as well.

## Genetic indicators of extinction risk

The Global Biodiversity Framework, adopted in 2022, suggests using effective population size (NE) to evaluate extinction risk: NE above 50 for short-term viability and above 500 for long-term viability [1]. The authors note that the universal applicability of these thresholds is debated, and that a revision proposes 100 and 1,000. All five species had current NE below the minimum threshold for long-term viability [1].

In some species, genomic diversity declined over a decade at rates comparable to or exceeding those reported for threatened and endangered species [1]. Earth.com reports that one lanternfish lost about 8% of its genetic diversity in 12 years. Demographic modeling indicates historical population declines in all five species [1]. Ecological niche models predict declining Gulf habitat suitability for most of them under future climate change scenarios [1].

The authors conclude that the results identify indicators associated with elevated extinction risk in Gulf mesopelagic species and raise the possibility of a broader, unnoticed crisis [1]. According to Peres, the findings challenge the idea that deep-sea species are naturally more resilient because they occupy vast environments.

## Sources

1. [nature.com](https://www.nature.com/articles/s41467-026-79098-0)
2. [Earth.com](https://www.earth.com/earth-science/animals-in-the-deep-ocean-may-have-less-protection-than-scientists-thought)

---

Source: RealTech, realtech.media — https://realtech.media/news/rt-6b5812631fa2eac0dc7ab3ad_five_gulf_of/